The main target is to aid patients with medicinally intractable seizures due to partial epilepsy who are to be treated by therapeutic surgery. The particular work of this laboratory is aimed at defining more exactly the locus of abnormal electrogenesis within the brain as an aid to the surgeon who uses implanted electrodes to seek lateralizing and preferably localizing guidance. As the rate of spread of electrical seizure activity is more rapid than the eye can follow on recording instruments, a computer method has been used to detect the site of the initial discharge and to follow the seizure as it is driven to other structures. This method has proved of considerable usefulness and has now been developed further in comparative studies in which the eventual pathological findings after operation have been correlated with the electrically predicted site of epileptogenetic tissue, and with the long-time clinical follow-up after removal of the incriminating tissue. Another newly added line of investigation, also aimed at discrete localization is the analysis of the end of the seizure: i.e. an exploration to see whether or not the exhaustion of discharge may be a clue to the most disturbed cells. The sequence of drop-out of discharge is being examined by computer analysis, for just as at the onset, the serial fall-out between structures is at intervals too short for definition, although for gross lateralization the effect can be striking indeed. Again, the long-term follow-up studies should enable us to check the electroencephalographic prediction against the pathology and clinical result.